Rock-drill



' G. H. Gun/IAN.

ROCK DRILL.

.APFLICATION- FlLED AUG.27, 1915- RENEWED JUNE 16, 1919- 1,382,779.

ROCK DRLLL. l APPLICATION man Auml, 1,915. afNews-n June m. 1,919. 1,382,779, Patented June 28, 1921.

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by r-V M @Wd-f Magg ROCK DRlLL.

APPLICATION FILED AUG.27, I9l5. RENEWED JUNE 16, |9191 Patented June 28, 1921 3 SHEETS-SHEET 3.

Georgel xvii/mg n,

,UNITED SIATES GEORGE H. GILMAN", OF CLAREIVIONT, HAVIPSHIRE,

saresti# OFFICE.

` MACHINERY COMPANY, or Granier/roam, NEW HAMPSHIRE' A CORPORATION or MASSACHUSETTS.

ROCK-DRILL.

Specification of Letters Patent. Patented June 28, 1921.

Application,y filed August 27, 1915, Serial No. 47,570. Renewed ,Tune 16, 1913. Serial No. 304,726. i

T0 all whom t may concern.' y

Be it known that I, GEORGE II. GILMAN, a citizen of the United States, and a resident lof Claremont, county of Sullivan and State of New Hampshire, have invented an Improvement in Rock-Drills, of which the following description, in connection with the accompanying drawings, is a specilication, like characters on the drawings representing like parts.

This invention relates to cutting tools, and more especially, though not exclusively, to rock drilling machines of that class in which liquid and gaseous fluid may be supplied to the drilled hole to lay the dust, cleanse the drilled hole, and expel the cuttings therefrom.

My invention will be best understood by reference to the following description, when taken in connection with the accompanying drawings of one illustrative embodiment thereof, while its scope will bemore par-V ticularly` pointed out in the appended claims. Y

In the drawings:

Figure l is a plan, partly in section, of a rock drilling machine embodying my invention;

Fig. 2 is a longitudinal section, partly 'in elevation, on line 2-2 of Fig. 1;

Fig. 3 is a sectional View, partly in elevation, on an enlarged scale, on line 3 3 of Fig. 2; A

Fig. 4 is a detail, central, longitudinal section, on an .enlarged scale, `on line A-A, Fig. 3, of the rear end of the machine showing the throttle valve in its closed position;

Figs. 5 to 8 inclusive,'are longitudinal sections showing the valve in its various positions of adjustment.` Each of these figures comprises two views, viz: A and B on lines A A and BB respectively of Fig. p

Referring to the drawings, and to the embodiment of my invention, which I have selected for illustration, I have there shown a rock drilling machine comprising suitable drill-bit percussion means, herein in. the form of a pressure fluid engine having a cylinder 9, inwhich a piston 10 is mounted to reciprocate. drill-bit 11 percussively inany appropriate manner, but for the purposes of illustration, I have shown a machine of the indirect or hammer type, in which the piston delivers The piston may actuate a a rapid succession of blows on the inner end` of the drill-bit, which is loosely held in 1ts path. In the illustrative example, the piston is provided with a hammer bar or extension 12, having splined 'connectlon with a suitable chuck 13, and

`provided with suitable rotating mechawhich in turn causes a step-'by-step rotative movement of the chuck andv the drill-bit held thereby, the drill-bit for this purpose being provided with suitable means, such for example as a pair of lugs 14, engaging slots 15 provided in the chuck. The latter, as is customary, may be, and is'herein, provided with a chuck bushing 16, which holds the drill-bit and defines its initial movement. In the example shown, the cylinder is provided with an elongated front cylinderhead 17, which inclcses and forms a mounting for the chuck Vand its associated parts.

The movements of the piston may be con trolled by any suitable means, as by the piston itself, or by a suitable pressure fluid actuated valve 18 of any appropriate form, such, for eXample,k as that forming y the subject-matter of United States Letters Patent No. 1,095,848, dated May 5, 1914. This valve is annular, or shell-like in form, and located preferably at the rear of and in line with the piston, a rear projecting portion 19 of which is adapted to enter the valve and partly close the same on the rear stroke of the piston.

The valve controls the admission of pressure fluid to opposite ends of the cylinderl from a pressure fluid supply space 20, as well as the exhaust from the opposite ends of the cylinder through an exhaust outlet 21. Suitable gaseous fluid, preferably compressed air, is supplied to the pressure supply space 20 by a flexible pipe 22, and is under the control of a throttle valve, which I will presently describe.

The drill-bit 11 is provided as usual with Y t cutting edges 23, and to the end that the cuttings may be expelled, the dust laid, and the cutting edges kept cool during the operation of the drill, the drill-bit is made hollow, and, as herein shown, is provided with an axial passage 24 extending from end to end. To supply the hollow drill-bit with liquid or gaseous fluid, or both, under pressure, I may employ two-tubes 25 and 26, one adapted to supply liquid and the other gaseous fluid. These tubes may be, and preferably are, coaxially arranged, and extend through a longitudinal and preferably axial perforation 27, provided in the piston. The inner tube 25, which in the present case is intended to supply liquid to the interior of the drill-bit, extends into and terminates within the latter, and'is of such diameter as to leave an annular space 28 of small area between the tube and the surrounding internal surface of the axial hole 24 of the drill-bit to provide for the entrance of gaseous fluid at the rear end of the drill-bit, whereby the liquid and gaseous fluid may be separately conducted into `and united within the drill-bit. The

outer tube 26, which is intended to conduct the gaseous fluid, may and preferably does terminate at the rear of the drill-bit, vand at a sufficient distance therefrom so that the gaseous fluid may build up within a chamber 29 within the drill chuck a body of gaseous fluid under pressure which will supply thevbore of the drill-bit, and in addition, what is equally important and one of the particular features of my invention, will serve to prevent the entrance of water and sludge into the cylinder. This is very apt to take place when drilling upwardly directed holes, and, where the water and sludge find their way between the drill-bit and the chuck bushing into the space at the rear of the drill-bit, much damage may result to the rtool if the water and sludge find their way along the hammer bar and into the cylinder proper. .c

The tubes 25 and 26 extend rearwardly into, and are supported in some appropriate manner within a rear cylinder head or head block 30. The inner tube extends some distance rearwardly beyond the outer tube, and communicates through passages 101 (Fig. 4) and 102 with a valve 65 to which liquid is conducted through the passage 81 from any suitable water supply typified by the coupling 68 connected to a water supply hose 64.

Gaseous fluid, preferably air, is conducted to the outer tube 26 through the passage 103 from the chamber 104, which communicates with the valve mechanism hereinafter described, through the radial passages 105, the 'passage 106 in the plug 107, the chamber 108, and the passage 109.' Y

I have found it advantageous tc locate several of the before described passages in a vvalve containing block 110 in which I preferably screw a cylindrical air and water distributing block 111, adapted to receive the rear ends of the air-and water tubes 25 and 26. I may secure these tubes and prevent leakage by providing in the block 111 a cylindrical opening 112, which may contain the packing ring 113, the gland 114 `carried by the head of the water tube 25,

the annular ring 115, the gland 116 carried by the air tube 26, the packing ring 117 and the gland 118 which is pressed against the 'packing disk 119 when the block 111 is screwed in place, thereby pressing together and holding in proper relation all the'members contained in the cylindrical opening 112. I preferably proportion the annular ring 115 and the gland 116 so that an air chamber 120 is provided back of the air tube 25. In the annular ring 115 there may be turned the annular groove 121 which may be connected with the air chamber 120 by radial ports 122. Around the block 111 I prefer to provide a packing ring 123. In the rear of the block 111 is another cylindrical opening into which the-plug 107 is Screwed. This plug may be provided with a hexagonal head 124 which may serve, as illustrated, to retain a headV 125 serving to close theJ rear opening of the heard block 110. Y When it is desired to disassemble themachine the hexagonal head 124 is turned, thereby unscrewing the plug 107 and releasing the head 125. The block 111 may then be unscrewed and withdrawn from the head block 110, thereby permitting the withdrawal of the tubes 25` and 26 and theassociated parts.

In order that the supply of motiveV fluid to the cylinder, the supply of liquid to the drilled hole, and the supply of gaseous fluid to the drilled hole may be cordinately controlled, I preferably place them under the control of a single valve 65, which, as will be hereinafter described, in itsclosed position (Fig. 5) shuts oli' entirely the supplies of both gaseous fluid and water from the tool. Vhen the valve 65 is turned to the second position (Fig. 6) air is admitted to the air tube 25 and water to the water tube 26. In the third position (Fig. 7) air and water are still admitted to the tubes while the port to the hammer drill operating mechanism ispartially opened. 4The fourth position (Fig. 8) completesy the opening of the port to the drill operating mechanism while leaving open the air and water supply ports to the tubes. In Figs. 5, 6, 7 and 8, 126 represents the air supply chamber, 127 the air .controlling portion, and 128 the water controlling portion of the valve 65. TheV air supply to the tube passes out through the port 129. Water is introduced' to the valve 65 through the port 130,`and passesV out ico through the port 131 along the passage' 132 to the passagee1-33. Thejwater and air ports to the tubes areopen, as shown in Figs. 6, 7 and 8. The airport to; the-drill is partly, open in Fig, Z and fnlly open v In Fig. l all portsare closed. l

I have found this form. control to., be particularly advantageeus when used, incennection with the. othermechanism herein describedv as contained in the head block.; The construction and, organization is well adapted to withstand the jar and shockinseparable froml rockdrill operation; ,The relative arrangement of air and-water supplyl tothe tubes wherebytheair supplyI toltlie air tube 25 passes around -the more exposed passages, while thewater is confined tellbetter protected passages, insures-,against the` objectionable exterior leakage of water. Interior leakage is prevented iby; the air under pres,- sure which PIeventssuch, leakage even; if the packing provided proves defective The construction isv simple, not likely toget out of order, cheap to manufacture, Veasy to assemble and disassemblefandveryeiective in operation. e

While I have herein sho. ,n anddescribed one specific embodiment.` of my invention for illustrative purposes, and: have disclosed and 'discussed in detail the construction; and arrangement incidental to one' specific application-thereof, it is to be understood thatthe invention is, limited neither `tof the mere details or relative arrangement of parts, nor to its specific embodiment herein shown, but that extensive deviations from` the illustrated, form or embodiment ofthe'invention may be made, lwithin the scope" of the claims, without departing from the principlesjof. the invention. `j` Y 1 l Having thus described my invention, what I claim and desire by Letters VPatent toy procure is1fl v f n l V l. A rock drill comprising, in. combination, a hollow `drill Abit drill` bit percussion means; tubular means for conducting{air and water to said drill bit; a manually operable controlling means forcontrolling aolmission of air and waterV to said tubular means; anuair passage Connecting said controlling means; with saidtubular means; and

a water passage connecting saidV controlling' means with saidtubular means, said air pas- Yto sage vbeing located in the .rear of said water passage and so disposed as to lprevent leak; age therefrom. e Y

2. A rock drill comprising, in 'combi-nation, a `hollow drill bit; drill-bit percussion means; an air conducting tube disposed longitudinally of said drill for conducting air to said drill bit; a water conducting tube passing through saidair conducting tube and extending rearwardly therefrom; aheadv receiving the rear ends of bothofi said tubes;

' awater passage in said head for conducting water to said'watertube.; and means includingfan air passage in said head positioned rearwardlyiromsaid waterpassage for preventing'leakagetherefrom.V I 33S In arockfdnillj having a 'hollow ,drill bit andpercussijon means, the combination of twottnbes, one within, the other, for conducting water and gaseous fluid to. said hollow ,drillfx bit, and lterminatingV rearwardly in a headi vhavinga removable exterior` portion, water, conducting ,means for conducting waterto one of said-tubes, andr-meansincludingl an air` chamber-inthe rear of said head adjacent said :removable portion for preventingpleakage from said' water conduct- `ingmeans.... fr

i 4., Ina rock drillhaving a hollow drill bit andv percussive means, the combination ofi'a rear head, tubular meanslfor Vconducting air and water from said head to said hollow drill bit, saidtubular means terminating in said head-,a removableportion secured to said lieadfandk1neans including an elastic pressure Huid containing4 chamber` adjacent said removableportion for preventing leakageof the water. a Y, v` 1 f `5. Ina roclrdrillhaving a hollow drill bit and percussivemeans, the combinatioIlVrOftubular; fiuid, conducting, .meansl for conducting fluid to saiddrill-bit, and a rear cylinder headhaving agchamber alined with said conducting Vmeans-,fsupporting means for said conducting -means-positioned in said chamber .and having provisioni'or supplying liquid-to said conducting means, an Opening in the lrear of said;y chamberthrough which said supporting; meansv and said tubular means may beawithdrawn, a cover for said opening, and-1an elastic; pressure fluid con- Y tainingchamber intermediate said, supporting means-and said cover. i

. 6. In a rock; drill, the combination ot a cylinder, percusjsive means, a hollow drill steel,aV rear head, tubular means for conducting gaseousluid anda liquid from-said rearheadto said drill steel, a tubular means receivingl memberfsubstantiallyalined `with i said tubular meansand removably secured in said baclr head, and clampingmeans tor simultaneously clamping said. tubular means to said rearfheadupon movement of said receivingmember.: ,i i n m7. Ina rock drill, the combination with a cylinder, percussive meanstherein, a hollow drill steel, concentricallydisposed gaseous Huid and liquid-tubes communicating therewith, a rear head, `a plug adjustable therein and inclosing the rear ends of said tubes, andfmeans disposed'within said plug and carriednupon: the endsofsai'd tubes for clamping both-of the latter to said head upon `adjustment of said plug.

8. In a1-rock drill, `the combination with a cylinderypercussive means therein, la hollow drill steel, concentrically disposed gaseous fluid and' uqeid tubes Commenicasng there with, a rear head', aplug adjustable therein and inclosing the rear ends of said tubes, and

means carried in said plug fior spacing apart' the ends of ,said tubes and clamping the same to said head upon adjustment of said plug;A

9.v In a rock drill,`the'combination with'a cylinder, percussive means therein, a hollow drill steel, veoncentrically disposed 'gaseous uid and liquid tubes communicating:there-r with, a rear head, a plug inclosing the rear ends of said tubes, means within saidplug and disposed around the ends of said' tubes for clamping thelatter to said head upon adjustment of said plug, and means for supplying gaseous fluidand liquid to said tubes irlicluding separate passages through said p u A f l In a rock drill, the combination with a cylinder, percussive means therein, a hollow drill steel, concentrically disposed gaseous fluid and liquid tubes lCommunicating therewith, a rear head; a plug inclosing the rear ends of said tubes, means within said plug and vdisposed around the ends'of said tubes for clamping theY latterVV to 4saidfhead uponladjustment of said'v plug, means for supplying gaseous fluid and liquid to` said tubes' including separate passages through said plug, and sealing means surrounding said plug at one side of sai'dliquid passages.

11. Inra rock drill,--thecombination ofa cylinder, percussive means, a hollow drill steel, a rear head, tubular vmeansffor `con ducting gaseous fluid and aV liquid from said rear head to said drill steel, va tubular` means receivingy member substantiallyv alined with said tubular means'and removably "secured in said rear head, gaseous fluid andliquid conducting means in said receiving'member for conducting gaseous fluid and' liquid to said tubular means, and a valve for controlling the flow of gaseous fluid'and liquid.

12. In a rock drill, a cylinder,'percussive means therein, a hollow drill steel, concen- Vtrically disposed gaseous fluidand liquid tubes communicating therewith, a rear head, an adjustable plug in said head inclosing the' rear ends of said tubes, clamping means controlled by said plug Lfor'clamping both lof said tubes to said head upon adjustment of saidplug, a removable member inclosing the end of said plug, and means for clamping the latter to said plugff Y v 13. In a rock drill, a cylinder, percussive means therein, a hollow' drill steel, eoncentrically disposed gaseous fluid and liquid tubes communicating therewith,a*rear' head, a removable plug inclosing the rearends of said tubes, means inclosed by said plug for clamping said tubes to saidl head upon movef ment of said plug, and a removable member inclosing the end of said-plug, said head and plug and removable meinber'being provided with passages for supplying gaseous nasen-7e cylinder,v percussive means, a? hollow 'drill steel, a rear head,-a water tube for conduct'- 'ing watersfromlsai'd rear'hea'd to said drill SteeLlfz'tnv air tube for conducting 'air-tosaid drill"'steel,vone of said-tubes being located rwithin-'the other and'eXtending rearwardly therefrom, aY removable Vmember located in said rear'head 'and supportingan air tube 'support fand aI water tube support, packing operatively? positioned between saidY "air tube support and said water-tube support, and means forcompress'ing'said packing.

15; In a rock drill-,the combination of a cylinder, rpereussive"means, fa hollow drill steel,a vrear-head, a water tubefor conducting waterfrom saidrear head tosaidV drill steel, an air 4tube for conducting air to said drill steel, oneof said tubes being located within the other and extending rearwardly therefrom, a removableqmember located in said rear head and supporting an air tube support and a water tube support,V packing vsaid rearv head andvsupporting an' airtube support and a waterftube support, packing operatively positioned between said air tube support and saidwater tube support, and compressionl means kwhereby rotative'movement of saidremovable member tightens said packing. j 17. In 'a'rock drill, the combination of a cylinder, percussive means, a hollow vdrill steel, a-rear head, a water tube for conduct- Y ing water from said rear head to said drill steel, an air tube for conducting air to said drill steel, one of said ltubes being located withinthe other and extending rearwardlyV i therefrom, a removable' member located in said rear headfa'ndoperatively supporting said air tube and said water tube,'an opening inthe rearV of said rear head whereby said removable member may be removed, a cover forfsaid opening, an'dfanair chamber adjacent-the joint between'said. rearl head and saidfcover. 4 v 18.' In a rook drill, 'the combinationv of a cylinder, percussivemeans, ahollow drill steel, a rear head, a water tube for conducting water-from Vsaid rear head to said drill steel,

anair tube for Vconducting air to said drill Steel, one of said tubes being located within the other and extending rearwardly` therefrom, a cylindrical member removable through an opening in said rear head and in which said tubes terminate at their rear ends, said member having separate passages therein for supplying air and water to said tubes and a cover for said opening.

19. In a rock drill, the combination of a cylinder, percussive means, a hollow drill steel, a rear head, a water tube for conducting `water from said rear head to said drill steel, an air tube for conducting air to said drill steel, one of said tubes being'located within the other and extending rearwardly therefrom, a removableV member located in said rear head and operatively supporting said air and water tubes and having separate passages communicating therewith, and a single control valve vproviding ports for simultaneously conducting air to one of said tubes and water to the other of said tubes.

20. In a rock drill, the combination of a cylinder, percussive means, a hollow drill Steel, a rear head, a water tube for conducting water from said rear head to said drill steel, an air tube for conducting air to said drill steel, `said water tube being located within the other and extending rearwardly therefrom, a removable member located in said rear head and operatively supporting said air and water tubes and having separate passages communicating therewith, and a single control valve providing ports for simultaneously conducting air to one of said tubes and water to the other of said tubes without admitting air to said percussive means.

`21. In al rock drill, the combination of a cylinder, percussive means, a hollow drill steel, a rear head, a water tube for conducting water from said rear head to said drill steel, an air tube for conducting air to said drill steel, said water tube being located within the other and extending rearwardly therefrom, a ,removable member located in said rear head and operatively supporting said airand water4 tubes and having separate passages communicating therewith, and a single control valve providingports for simultaneously conducting air to one of said tubes, water to the other of said tubes an air to said percussive means.

i 22. In a'rock drill, the combination of a cylinder, percussive means, -a' hollow drill steel, a rear head, a water tube for conducting water from said rear head to said drill steel,an air tube for conducting air to said drill steel, said' water tube being located within said air tube and extending rearwardly therefrom, a removable member located in said rear head and operatively supporting said air and water tubes and having separate passages communicating therewith,

and a single control valve providing ports for simultaneously conducting a full supply of air to said air tube, a full supply of water to said water tube, and a restricted supply of air to said percussive means.

23. In a rock drill, the combination with a cylinder, of percussive means therein, a hollow drill steel, a rear head for said cylinder, separate coaxially disposed gaseous fluid and liquid conducting tubes in said cylinder communicating with said steel, and means for securing saidtubes in rigid relation to said head comprising a removable member disposed in said head between the ends of said conducting tubes and operative positively to prevent movement of said ends toward each other.

24. In a rock drill, the combination with a cylinder, of percussive means therein, a hollowv drill steel, a rear head for Asaid cylinder, separate coaxially disposed gaseous fluid and liquid conducting tubes communieating with said steel and terminating at Y their rear ends in said head, a removable spacing member disposed in said head between the ends of said conducting tubes and operative positively to prevent movement of said ends toward each other, and detachable means for clamping said elements in said head. y

25. In a rock drill, the combination with a cylinder, of percussive means therein, a hollow drill steel, a rear head for said cylinder, separate coaxially disposed gaseous fluid and liquid conducting tubes in said cylinder communicating with said steel, means for securing said tubes in rigid relation to said head comprising a removable spacing member disposed in said head betweenthe ends of said conducting tubes and positively preventing their movement toward each other, and fiuid conducting means in said spacing member.

26. In a rock drill, the combination with a cylinder, of percussive means therein, a hollow drill steel, a rear head for said cylinder, separate coaxially disposed gaseous fluid and liquid conducting means in said cylinder extending from said head and communicating with said steel, a spacing member disposed in said head between the ends of said conducting means andpositively preventing their movement toward each other, and a single clamping member for retaining saidconducting means in said head.

27. In a rock drill, the combination with a cylinder, of percussive means therein, a' hollow drill steel, a rear headfor said cylinder, separate coaxially disposed gaseous fluid and liquid conducting means communieating with said steel and terminating in said head, a spacing member disposed in said head between the ends of said conducting means and positively preventing their movement toward each other, a single clamping member for retaining said conducting means in said head, and fluid conducting means in said spacing member.

28. In a rock drill, the combination with a cylinder, of percussive means therein, a hollow drill steel, a rear head, separate coaxially disposed gaseous fluid and liquid conducting means communicating with said steel and terminating in said head, spacing means in said head between the ends of said conducting means, a single clamping member for retaining said conducting means in said head, and fluid conducting means in said spacing Vmeans and clamping member.v

29. The combination with a percussive tool, of a hollow drill steel, and means for supplying a cleansing fluid thereto comprising a rear head, a gland therein having a socket formed therein, a plurality of tubes detachably secured in said socket, said gland and tubes being insertible into said head from the rear thereof', and means for conducting fluid to said tubes.

30. The combination with a percussive tool, of a hollow drill steel, and means for supplying a cleansing fluid thereto comprisingl a rear head, a gland therein having a socket, a plurality of fluid conducting means communicating with said socket, and a plurality of tubes detachably secured in said socket in communication with said fluid conducting means.

31. The combination with a percussive tool, of a hollow drill steel, and means for supplying a cleansing fluid thereto comprising a rear head,- a` gland therein having a socket, a plurality of tubes extending into said head, spacing means therefor disposed in said socket, anda packing surrounding one of said tubes and compressed upon movement of said gland.

y32. In a rock drill, the combination with a rear cylinder head, of a plurality of coaxially disposed tubular gaseous fluid and'y liquid conducting means extending into the same, an axially recessed clamping member having a passage communicating with one of said tubes, and a spacing member spacing the ends of the tubesextendingvinto the recess in said clamping member and having a passage communicating with another of said tubes. Y f

33.' In a rock drill, the combination with acylinder, of percussive means therein, a hollow drill steel, a rear head,a plurality of coaxially disposed gaseous fluid and liquid conducting means disposed axially of said piston, spacing means between'the same, a clamping member in'said head and axially alined with said spacingmeans and removable through said head, and a cover plate inclosingthe outer end'of said clamping member.

34. Ina rock drill, the combination with a cylinder, percussive means therein and a hollow drill steel, of separate coaxially dis.- Y

steel, each of. said tubes being provided with Y an annular collar, and spacing means between said collars. I

36. In a rock drill, the combination with a cylinder, percussive means therein and a hollow drill steel, of separate coaxially disposed gaseous fluid and 'liquid conducting tubes to conduct cleansing fluid for said` steel, each of said tubes being provided with an annular collar and spacing means between said collars, said spacing means cooperating to supply fluid to one of' said tubes.v 37. In a rock drill, the combination with a cylinder, percussive means therein and a hollow drill-steel, of separate'coaxially.'diss posed gaseous fluid and liquid conducting tubes to. conduct cleansingy fluid forsaid steel, and spacing means disposedV between the rear ends of said tubes, said tubes havingv portions abutting against the opposite ends of said spacing means. v 38. In a rock drill, the combination with a cylinder, percussive means therein and a hollow drill steel, ofy sepa-rate coaxially disposed gaseous fluid and liquid conducting tubes to conduct cleansing fluid to said steel, and spacing means into one end of which one of said tubes partially projects and with which a portion ofsaid tube valso has lateral engagement and against the opposite end of which a portion ofsaid other tube abuts.

39. In a rock drill, the combination with a cylinder, of percussive means therein, a hollow drill steel, a rear head, v'separate coaxially disposed gaseous .fluid andiliquid conducting tubes to conduct cleansingfluid to said steel, spacing means in said head between the ends of said conducting tubes, and detachable means for clamping one' of said elements against said spacing means.

40. In a rock drill, the combination withV a cylinder, percussive means therein and a hollow drill steel, of separate coaxially disposed gaseous Iluid and liquid conducting tubes for supplying cleansing fluid tof'said steel, and means for holding'said tubes in said cylinder comprising spacing means disposed between the rearl ends of said tubes, said tubes having portions abutting against spacially separated opposed surfaces of said spacing means. -V

41. In a rock drill, the combinationwith a cylinder, a piston reciprocable therein, a

, hollow drill steel, coaxially disposed gaseous fluid and liquid conducting tubes for supplying cleansingV fluid to said hollow drill steel, the inner of said tubes projecting reari wardly further than the outer thereof, a rear head, a plug adjustable coaxally with respect to said tubes, a flange upon the inner one of said tubes, a perforated collar through Vwhich said inner tube extends, and a packing surrounding the outer of said tubes, said plug being adjustable to clamp said flange into engagement with said collar and to co1npress said packing about said outer tube.

42. In a rock drill, the combination with -a cylinder, a piston reciprocable therein, aA

i hollow drill steel, coaxially disposed gaseous able to clamp said perforated collar in tight engagement with the flanges on said tubes.

4:3. In a rock drill, the combination with a cylinder, a piston reciprocable therein, a hollow drill steel, coaxially disposed gaseous fluid and liquid tubes for supplying cleansing fluid to said hollow drill steel, the inner of said tubes projecting rearwardly farther than the outer thereof, a rear head, a plug adjustable therein longitudinally with respect to said tubes, a perforated collar having a recess therein, the inner of said tubes extending longitudinally through said collar and the outer of said tubes projecting into said recess, a flange upon the inner of said tubes engaging the rear end of said collar, and a packing surrounding the outer of said tubes forwardly of said collar, said plug being adjustable to clamp said flange into engagement with said collar and to compress said packing about the outer tube.

In testimony whereof, I have signed my name to this Specification, in the presence of two subscribing witnesses.

GEORGE H. GILMAN.

Witnesses:

WALLACE A. ROBERTS, C. A. LOVELAND, Jr. 

